Catalyzer



Patented May 17,1932

UNITE TATES PATENT ()FFICE FRITZ JOST, OF HERNE-BORNIG, GERMANY,ASSIGNOR TO PATENTVERWERTUNGS A. G.

ALPINA, S. A. POUR ILEXPLOITATION DE IBREV'ETS ALPINA, PATENTS EX-PLOITATION CY. ALPINA, LTD., OF BASEL, SWITZERLAND GA'I'ALYZER NoDrawing. Original application filed. July 31, 1930, Serial No. 472,203,and in Germany August 3, 1929.

Divided and this application filed August 12, 1931.

My invention refers to the oxidation of ammonia and more especially to anew catalyzer for use in this process.

In this process platinum wire gauze or a gauze made of platinum alloyshas been used, this gauze being formed with very narrow meshes, theyield obtained being about 90- 93%.

In the practice of this process a mixture in of ammonia and air oroxygen containing gas is conducted through the platinum Wire gauze atordinary pressure and at a temperature varying between 650 and 800 C.

I have now found that I can considerably increase the yield, if I useplatinum wire gauze which has been subjected to a mechanical treatment,for instance by pressing, forg ing or rolling.

If the gauze is for instance placed in a if) hydraulic press andsubjected therein during one half minute to a pressure of about 50 atms.per 100 square centimetres, its activity will be greatly increased and,if used in the process above mentioned, the yield of nitrogen oxide willrise to about 97%.

Instead of platinum the alloys of platinum can be used. The termplatinum used in the claim is meant to include the alloys.

Example A mixture of ammonia gas and air containing about 9% by volumeammonia was carefully deprived of all dust particles and was thenconducted in contact with a platinum Wire gauze, which had previouslybeen Serial No. 556,713.

Various changes may be made in the details I subjected during about onehalf minute to a mechanical pressure of atms. per 100 squarecentimetres. The number of meshes per square centimetre was 1024, theplatinum gauze employed weighed 10 grams, the velocity of flow of thegas mixture Was 8085 liters per minute, the temperature of the gauzevaried between 670 and 720 C. 97% of the ammonia was converted intooxides of nitrogen.

